非饱和粉煤灰抗剪强度的时间效应及其预测

Time effect of shear strengths of unsaturated fly-ash and its prediction

粉煤灰是一种工业废料,常用作路基工程填料,而影响粉煤灰工程性质的因素有很多.为了探讨不同含水率以及龄期对粉煤灰强度的影响,对粉煤灰进行了一系列直剪试验,得到了相同干密度不同含水率以及不同龄期下的抗剪强度.试验结果表明,粉煤灰的抗剪强度和黏聚力均随试样饱和度的变化而变化,并随龄期的增加而增大,内摩擦角略微增加但变化不大.最后,还应用非饱和土强度理论和土水特征曲线对非饱和粉煤灰强度进行了预测.

Fly-ash is an industrial waste material, and is often used as a filling material in subgrade engineering. Many factors affect engineering properties of fly-ash. To investigate the effect of water content and age on the strength of fly-ash, a series of direct shear tests on a fly-ash are carried out. Relations between water content or age and shear strength with the same dry density were obtained. The results show that the shear strength and cohesion of the fly-ash change with variation of the saturation degree and increase with age, while the internal friction angle changes a little. Finally, shear strength of unsaturated fly-ash is predicted using unsaturated soil mechanics and soil-water characteristic curve （SWCC）.